Active Vocabulary:

adapt - адаптировать, приспосабливать

tracked vehicle - гусеничное транспортное средство

raise - поднимать

shape - форма

layer - слой

soil - почва, земля

forward - вперед

Volume - объем

cut - резать, срезать

acceptance - принятие

contractor - подрядчик

meet the demands - отвечать требованиям

suit - подходить, соответствовать

reliable - надежный

precise - точный

option - выбор

pavement - тротуар, мощеная дорога

durable - прочный, долговечный

Exercise 1.Answer the following questions:

1. When were the first bulldozer designs made?

2. What were those machines equipped with to do earthmoving jobs?

3. What specialized blades have been developed?

4. What bulldozer manufactures do you know?

5. What do bulldozer improvements include?

6. Why is Caterpillar the best known maker of bulldozers?

Exercise 2.Translate the following sentences, paying attention to the Conditional Clauses:

1. If bulldozers had not become bigger and more powerful they wouldn’t be able to

do large earth work.

2. Machines are used provided there are heavy and numerous operations.

3. If one uses bulldozers with GPS technology, grade control will be more precise.

4. People had not been able to build modern houses unless they had created

powerful machines.

5 If the machine were more versatile, it would be more useful.

6. This crane could be used provided its lifting capacity was larger.

7. They wouldn’t have used this tractor unless it had suited their needs.

8. Had they more modern equipment, their work would be more efficient.

Exercise 3.Translate the following sentences, paying attention to the underlined words:

1. The machine provided with a powerful engine will give much energy for work.

2. The friction force is directly proportional to the speed provided the latter is not

too high.

3. Bulldozers are very versatile provided they are used with numerous attachments.

4. If a tractor is equipped with a blade it can peel layers of soil and push it forward.

5. It is always necessary to determine if the stress is not too high for a given

structure.

6. The work is more efficient if the building site is provided with all necessary

equipment.

8. The builders wanted to know if the equipment would be delivered to the site in

time.

Exercise 4.Translate the text without a dictionary:

Text B

ROAD ROLLERS

The first road rollers were horse-drawn, and were probably just borrowed farm implements.

Since the effectiveness of a roller depends to a large extent on its weight, self-powered vehicles replaced horse-drawn rollers from the mid 1800s. The first such vehicles were steam rollers. Double-cylinder designs were preferred. Single-cylinder steam rollers were uncommon and unpopular, as the power impulses from the steam engine would produce slight waves in the road. Some road companies in the United States used steamrollers through the 1950s, and in the UK, some remained in commercial service until the early 1970s.

As internal combustion engine technology improved during the 20th century, kerosene-, gasoline- (petrol), and diesel-powered rollers gradually replaced their steam-powered counterparts. The first internal-combustion powered road rollers were very similar to the steam rollers they replaced. They used similar mechanisms to transmit power from the engine to the wheels, typically large, exposed spur gears. Some companies did not like to employ them as the engines of the era were typically difficult to start, particularly the kerosene-powered ones.

In fact, all road rollers in commercial use now use diesel power.

Initial compaction of the substrate is done using a pneumatic-tyred roller, with two rows (front and back) of pneumatic tyres. The flexibility of the tyres, with a certain amount of vertical movement of the wheels, enables the roller to operate effectively on uneven ground.

Notes:

borrow - заимствовать

implement - инструмент, прибор

slight - легкий

counterpart - копия, двойник

spur gear - цилиндрическая шестерня

Unit 4

Grammar: Gerund;

Ing-forms

Text A

DUMP TRUCK

A dump truck is a truck used for transporting loose material (such as sand or gravel) for construction. A typical dump truck is equipped with a hydraulically operated open-box bed hinged at the rear, the front of which can be lifted up to allow the contents to be emptied on the ground behind the truck at the site of delivery.

The dump truck was first made in Saint John, New Brunswick when Robert T. Mawhinney attached a dump box to a flat bed truck in 1920. The lifting device was a winch attached to a cable that ran over a sheave (pulley) mounted on a mast behind the cab. The cable was connected to the lower front end of the wooden dump box which was attached by a pivot at the back of the truck frame. The operator turned a crank to raise and lower the box. Today, virtually all dump trucks operate by hydraulics and they come in a variety of configurations each designed to accomplish a specific task in the construction material supply chain.

A standard dump truck is a full truck chassis with a dump body mounted to the frame. The dump body is raised by a hydraulic ram mounted between the truck cab (traction unit) and the dump body (semi-trailer).

A standard dump truck has one front axle, and one or more rear axles which typically have dual wheels on each side. The largest of the standard dump trucks has seven axles. The rear two axles are powered and the front axle is the steering axle. The intermediate axles are present to support the weight over the length of the chassis and sometimes to provide additional braking power. The short wheelbase of a standard dump truck makes it more maneuverable than the higher capacity semi-trailer dump trucks.

An articulated dump truck has a hinge between the cab and the dump box. Steering is accomplished via hydraulic rams that pivot the entire cab. This vehicle is highly adaptable to rough terrain.

A transfer dump is a standard dump truck which pulls a separate trailer which can also be loaded with aggregate (gravel, sand, asphalt, clinker, snow, wood chips, etc.). Transfer dump trucks typically haul between 26 and 27 tons of aggregate per load.

A semi bottom dump is a 3-axle tractor pulling a 2-axle trailer with a clam shell type dump gate in the bottom of the trailer. The key advantage of a semi bottom dump is its ability to lay material in a row. In addition, a semi bottom dump is maneuverable in reverse.

Double and triple bottom dumps consist of a 2-axle tractor pulling one single-axle semi-trailer and an additional full trailer (or two full trailers in the case of triples). These dump trucks allow the driver to lay material in rows without leaving the cab or stopping the truck. The main disadvantage is the difficulty in backing double and triple units.

A side dump truck has hydraulic rams which tilt the dump body onto its side, spilling the material to either the left or right side of the trailer. The key advantages of the side dump are that it allows rapid unloading and can carry more weight.

Dump trucks are normally built for some amount of off-road or construction site driving; as the driver is protected by the chassis and height of the driver's seat, bumpers are either placed high or omitted for added ground clearance.

Another safety consideration is levelling of the truck before unloading. If the truck is not parked on a relatively horizontal ground, the sudden change of weight and balance due to lifting of the skip and dumping of the material can cause the truck to slide, or even - in some light dump trucks - to turn over.